In marine based seismic acquisition systems, one or more vessels tow seismic sources including vibrational sources and impulse sources. Each vessel can pull a single source or an array of sources. These source arrays can include one or more strings. Each string includes one or more seismic sources and is connected to the towing vessel using an umbilical and a head module. Spacing among the strings in the source array and the overall spread of the source array are maintained using, for example, an arrangement of spreaders, active steering mechanisms such as “birds” and cables or ropes. The desired depth of each string and in particular the seismic sources along each string are maintained using one or more flotation devices spaced along the length of each string from the head module through the seismic sources.
Conventional towed seismic source arrays locate the seismic sources from the surface of the water down to a maximum depth of about 12 meters. However, certain applications and operational conditions of the marine based seismic source require sources to be towed at a depth greater than about 12 meters. However, the conventional arrangement of source arrays does not facilitate these deeper seismic source deployments. Therefore, seismic source modules and arrays of seismic source modules are desired that can be towed in a marine environment at depths exceeding 12 meters.